Brush structure



Feb. 14, 1956 R. F. KOCH BRUSH STRUCTURE Filed April 7, 1950 ll L4 L8 I] INVENTOR. Roy F Koch W J, )Zam ATTORNEY.

niteti BRUSH STRUCTURE Roy F. Koch, Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ghio My present invention relates to the art of cleaning devices and more particularly to a brush strip particu larly adapted to the requirements of high rotary speed, small diameter cylindrical brush structures such as are commonly used in the nozzles of suction cleaning devices.

The problem of providing a satisfactory brush strip for the small diameter high rotary speed agitator commonly used in the suction nozzle of suction cleaning devices is peculiarly difiicult. in devices of the foregoing character the permissible bristle extension beyond the outer surface of the agitator cylinder is limited and the bristle extension within the agitator body is limited by hearing mountings and other internal structures in the agitator construction. The brush bristles must have a certain degree of flexibility to avoid abrading carpets and other floor coverings and to perform their cleaning function properly; nevertheless they must be strongly anchored to withstand the high centrifugal and impact forces to which they are subjected in usage. The brushes used in agitators for suction cleaning devices should be readily replaceable, preferably by being constructed so that they can slide into a retaining structure from the end of the agitating cylinder, and the backing structure of the brush should be longitudinally flexible to some degree so that the same way be made in a simple mould as a straight back and then twisted into a helix as it is inserted into the agitator body. Additionally, the backing member should be light in weight and strong to minimize centrifugal stresses in the brush structure and to withstand the reaction stresses impressed upon it in use.

For reasons of economy and security it is desired that the bristle tufts and brushes of the character forming the subject matter of this application shall be individually stapled into the supporting backing member, that the staples shall be so arranged that they cannot collapse, pull through the backing member, shift in position to abrade the backing member or shift in such a manner that unequal stresses are placed upon the staples as the brush is in use.

Accordingly it is a principal object of my invention to provide a brush backing and bristle mounting structure particularly designed to meet the needs of agitator structures in suction cleaning devices which will satisfy the requirements above mentioned while being simple and economical to manufacture.

According to my invention I provide moulded plastic backing structure having sufiicient flexibility to twist into a helix as it is inserted into the retaining structure. The backing member is provided with a plurality. of cored bristle tuft seats therein which do not extend entirely through the backing member but terminate in a thin web separating the bristle tuft seats from a shallow channel on the base of the backing member which serves to shield the tangs of the staples and prevent them from catching upon and digging into the backing mounting structure. The thin web at the base of the bristle seat forms a base to position the bristles at a proper depth in the backing member and is the part of the backing through which the staples penetrate. The staples are set with their anchoring tangs extending parallel to the long axis of the bristle back and the thin plastic web above mentioned serve to prevent the bristles from collapsing, rotating or shifting position in response to the stresses produced in use of the brush by centrifugal forces and impact forces. By use of the thin plastic web above described I have found that the bristle tuft seat can be of very small dimensions thus providing for maximum free bristle length and maximum flexibility within the dimensional limitations inherently imposed upon the type of brush structure forming the subject matter of this application.

Other objects and advantages of the invention will be come apparent as the description proceeds when taken in connection with the accompanying drawings in which:

Figure 1 is a perspective view of a completed brush structure embodying my invention;

Figure 2 is a perspective sectional view of an agitator for suction cleaning devices illustrating a brush embody ing my invention mounted in the body thereof;

Figure 3 is an elevational sectional view drawn to an enlarged scale of the brush structure of Figure l; and

Figure 4 is a sectional view taken along the line 4-4 of Figure 3 and looking in the direction of the arrows.

Referring now to the drawing my present invention has been illustrated as applied to a brush mounting back and agitator for suction cleaning devices of the character illustrated in the copending application of John E. Vance entitled Brush Mounting For oLICllOIl Cleaners, filed concurrently herewith, and assigned to the assignee of the instant application. The present invention is concerned only with the bristle seating and mounting structure and may be applied to other brush back securing shapes than that illustrated in the drawing hereof.

As shown most clearly in Figure 1 my brush struc ture comprises an elongated brush mounting and backing element 1 which is moulded of suitable light weight, strong, bendable and dimensionally stable plastic such as polyethylene or polymerized vinyl plasticv Polyethylene is preferred because of its light weight and low cost. The backing element 1 is provided with a plurality of surface engaging bristle tufts 2 extending therefrom and secured in the backing 1 in a manner to be described more fully hereinafter.

Referring now to Figure 4, the plastic brush back 1 is provided with a shallow downwardly opening staple tang channel 3 in its base. Anchoring flan es 4 project from. opposite lateral sides of the backing 1 adjacent the top thereof and just below shallow guard flanges 5 for a purpose to be developed hereinafter. The top of the back 1 is provided with a flaring sided channel 6 positioned between the guard flanges 5 and extending approximately half way through the body of the backing i. A plurality of shallow slightly tapered bristle seating or anchoring holes 7 are cored into the back 1 and extend from the base of the channel 6 downwardly towards the channel 3 where they terminate approximately of an inch from the base of the channel 3 to leave thin webs 8 having a thickness of approximately of an inch separating the face of the seat 7 from the channel 3.

. A bristle tuft 2 is seated in each of the bristle seats or holesi'7. Each tuft consists of a plurality ofbristle strands looped to bring the free end into registry with each other. A U-shaped staple it extends around the bight portion of each of the looped strands of each bristle tuft. The legs of the staples extend through the thin webs 8 with the plane of the staples substantially parallel to the long axis of the brush back 1. After the legs of the U-shaped staples are pressed through the thin web 8 they are bent at right angles away from each other to lie along the upper face of the channel 3 between adjacent brush seats 7 as shown at 11 in Figure 3; thus the staples are gripped beneath and tightly against the heaviest portion of the plastic brush back 1 between adjacent bristle tuft seats 7. The staples are applied and clinched in a suitable stapling machine having an anvil extending into the channel 3 to bend and clinch the staple legs 11 into the position shown in Figure 3.

As shown most clearly in Figure 3 the staples are aligned with the long axis of the brush back 1 and the turned up tangs 11 of engaging staples 10 to extend in opposite directions toward each other in overlapping relationship.

The complete brush shown in Figure 1 illustrates the application of the invention to a brush strip designed for a particular agitator mounting construction. The guard flanges 5 and are raised and rounded as indicated at 12 to form end shields for the end bristle tufts.

Referring now to Figure 2 the brush back 1 is shown mounted in a helical slot 15 formed in the cylindrical shell of a rotary agitator structure 16 which is rotatably mounted upon a fixed shaft 17 by suitable bearing supports not shown. Adjacent the edges of the slot 15 the agitator shell is flat as indicated at 18 to overlie and bear on the top of the anchoring flanges 4 of the brush back 1. A channel mounting strip 20 is secured within the shell 16 to lie under and across the channel 15 and define a seat for the brush back 1 upon which the lower portion thereof bears. It is apparent from Figure 2 that the channel 3 provides a protected recess for the anchoring ends of the staples 10 which will prevent them from engaging and catching upon the channel member 20. The brush as originally made is preferably a straight structure as shown in Figure l but the plastic possesses suflicient flexibility to permit the same to advance into the helical form shown in Figure 2 as the brush is pushed into the channel 20 under the flat sections 18 of the cylinder 16 which define the edges of the retaining slot 15. It is also apparent from Figure 2 that the guard flanges 5 provide soft flexing shoulders which the bristles can strike under extreme flexure without bending around a hard and possibly sharpened metal edge in the agitator structure.

The base of the bristles is close to the base of the brush back 1 being spaced therefrom only by the depth of the shallow channel 3 and the thickness of the web 8. It is also to be noted that only a small portion of each bristle tuft 2 actually seats within the anchoring seat 7 to provide maximum free flexing bristle length. This assures the maximum flexing length with a given limitation on total bristle length. The channel 6 serves merely as the defining wall of a flexing limit which will not be reached under ordinary conditions of usage and which provide a smooth non-cutting surface for the bristles to contact under severe flexing due to heavy usage.

A typical brush structure made according to the invention has a web 8 of /32 inch thickness forming the bottom of a bristle hole 7 of inch depth and tapering from a diameter of 0.125 inch at its outer end to a diameter of 0.110 inch at the web 3. These dimensions point up the fact that the full length of the bristles is free except for slightly more than the part which is engaged by the staples. Where the terms shallow and thin are used herein in reference to the brush cavities 7 and webs 8, respectively, those terms refer to dimensions of the order given in the above example.

The thin plastic webs 8 have been found to be effective anchors for the staples 10 and to prevent them from collapsing to release the bristles and from rotating in usage.

The ends 11 of the staples should be aligned as illustrated in Figures 3 and 4 to apply centrifugal and impact stresses equally to each of the legs 11 on each staple 10 which then distribute such loads over a significant area of the heavy body portion of the brush back. This alignment of the staples prevents the staples from rocking from the position illustrated in Figure 3 to apply stresses upon the point of one or the other of the tangs 11 which would tend to dig the tang into and through the plastic brush back. The thin web 8 through which the staples extend serves another important function in that it prevents them from rotating into crosswise relation with respect to the brush back which action intends to produce the above mentioned digging of the ends of the tangs 11 and also tends to produce a destructive abrasion upon the brush back during usage. The thin, approximately of an inch thick web 3 has been found to provide a most effective anchorage for the staples without significantly decreasing the net effective flexing length of the bristles.

While I have illustrated and described the invention in considerable detail, it is to be understood that various changes may be made in the arrangement, proportion and construction of parts without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A brush strip comprising an elongated flexible plastic back provided with channels in opposite faces thereof having a common separating Wall, a plurality of spaced cavities in said separating wall opening into one of said channels and closed at their bottoms by thin plastic webs, a bristle tuft in each of said cavities, a staple securing each of said bristle tufts to said plastic back, each of said staples having a bight portion looped over a bristle tuft in a cavity and leg portions piercing the plastic web forming the bottom of said cavity in spaced relation to each other and bent to lie in said other channel against said base between adjacent cavities, said staples being positioned with their bight portions and the bent ends of their leg portions lying parallel to the length of said channels.

2. A brush structure comprising an elongated base member of flexible plastic material, one face of said base member being formed with a plurality of spaced apart brush tuft receiving cavities along its length, said base member being formed with a shallow channel in a face thereof opposite to said one face, each of said cavities extending toward said channel and being closed at the bottom by a thin web of plastic material forming a portion of the base of said channel, a bristle tuft in each of said cavities, each of said bristle tufts consisting of a plurality of bristles bent into U-shape to bring their free ends together, and a staple straddling the bight portions of said U-shaped bristles of each bristle tuft and having leg portions piercing said web and bent to lie against the base of said channel between said brush receiving cavities.

References Cited in the file of this patent UNITED STATES PATENTS 1,121,652 Montgomery Dec. 22, 1914 1,448,744 Hastings Mar. 20, 1923 2,251,327 Cromie Aug. 5, 1941 2,261,768 Jones Nov. 4, 1941 2,271,551 Hoover Feb. 3, 1942 2,469,256 Brakman May 3, 1949 

